Fluid and material flow meters that create a section of differential pressure through the use of diametrically opposed segmental wedges are known. Such devices are disclosed in U.S. Pat. Nos. 4,237,739 and 4,926,698. It is well known that wedge flow meters are particularly adapted for difficult to measure flows such as high viscous fluids, slurries, waste water and fluids with suspended solids. While this type of flow meter has been well accepted for these special applications it suffers from several disadvantages, the foremost of which is the requirement that the flow reaching the differential pressure producing wedge must be undisturbed. That is, flow disturbances caused by pipe elbows, reducers, expanders, valves or similar irregularities must be conditioned by relatively long runs of straight pipe upstream and downstream of the flow meter before the flow meter can deliver accurate results. Depending on the configuration of the irregularity, the straight length of the upstream conduit may have to be ten to fifteen times the pipe diameter and the downstream straight pipe length may have to be up to five times the pipe diameter.
Accordingly, it is the primary purpose of the present invention to provide a primary flow measuring element utilizing a differential pressure producing wedge that incorporates additional upstream devices that condition the flow and eliminate the necessity of providing long conduit lengths ahead of and downstream of the flow element.